The subject matter of this invention relates to a staged oxy-fuel burner that may be used as an oxy-fuel burner or an air-oxy-fuel burner to enable a spacious mode of combustion, low NOx, and a controlled heat flux profile.
Oxy-fuel and air-oxy-fuel burners are used in a wide range of applications. In some applications, it is desirable to have a burner with a rapid heat flux combined with low NOx, operating in an oxy-fuel or air-oxy-fuel mode. In other applications it is desirable to have a burner with uniform heat flux combined with low NOx. In yet other applications it is desirable to have a heat flux profile that can be adjusted to accommodate a particular furnace or heating scenario.
Conventional oxy-fuel burners and methods for using burners for entraining furnace gas into the combustion zone are described in U.S. Pat. No. 6,866,503 B2, U.S. Pub. No. 2003/0148236 A1, and US Pub. No. 2007/0254251 A1, which are hereby incorporated by reference in their entirety. High momentum nozzles in those burners can be susceptible to fouling and clogging, particularly when operated in dusty or dirty environments. Another conventional burner known as a “pipe-in-pipe” burner is disclosed in FIG. 21.4 of section 21.4.1 of the Industrial Burners Handbook, CRC Press 2004. There is a need in this art for a burner and method that provides spacious combustion, reduced NOx, and a controllable heat flux profile.